3GB will give you much more breathing room. You can get away with 1.5GB but there are some situations where you'll be VRAM limited. I've broken 1.5GB usage at 2560x1440 personally.
Originally Posted by Skoobs
also, how is palit? could save some money by getting their version of whichever card i end up getting.
I'll vouch for Palit. I just went through a double RMA through them and it was pretty painless. The turn around time was actually faster than I've experienced with MSI, and they shipped brand new, retail boxed cards instead of refurbs.